Pressure failure warning system

ABSTRACT

A valve, especially useful to anaesthetists, for warning of the existence of a low pressure in a main supply and to transfer to a reserve supply upon the existence of a lower main supply pressure.

United States Patent E. James Treloar Vancouver, British Columbia,Canada 826,984 May 22, 1969 June 8, 1971 Rogar Products Ltd.

Vancouver, British Columbia, Canada Inventor Appl. No Filed PatentedAssignee PRESSURE FAILURE WARNING SYSTEM 7 Claims, 6 Drawing Figs.

U.S. C1 137/113, 1 37/1 1 1 Int. Cl 605d 16/06 Field of Search 137/1 14,

[56] References Cited UNITED STATES PATENTS 3,033,220 5/1962 St Clair137/557- 3,342,201 9/1967 Grogono 137/112 3,351,088 11/1967 Jensen137/557 Primary Examiner-Laverne D, Geiger Assistant Examiner-William H.Wright Attorney-Fetherstonhaugh & Co.

ABSTRACT: A valve, especially useful to anaesthetists, for warning ofthe existence of a low pressure in a main supply and to transfer to areserve supply upon the existence of a lower main supply pressure.

PATENTED JUN 81% 3583,4221

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PATENTEU JUN 8197i SHEET 2 UF 3 PATENTED JUN 8197i SHEET 3 OF 3 mvlm'rouE. JAMES TRELOAR ATTORNEYS PRESSURE FAILURE WARNING SYSTEM BACKGROUND OFTHE INVENTION This invention is concerned with a device for warning thata gas supply is at or below a predetermined pressure and forautomatically switching to a reserve supply at that or anotherpredetermined pressure.

The invention has particular but not necessarily exclusive, applicationin monitoring and controlling gases such as for example oxygen, usedwhile administering anesthetics Whilst the invention does not seek tocompletely relieve the anesthetist of the responsibility of maintaininga constant and careful watch on the supply of gases to the machine fromwhich the gases are administered to the patient it is a system whicheffectively will give a warning of a low level of gas supplied to themachine. It will also effectively save on gas wastage by allowing supplycylinders to be emptied to a greater extent than was hitherto consideredsafe.

BRIEF SUMMARY OF THE INVENTION According to one aspect of this inventionthere is provided a warning system which has a main gas supply and areserve gas supply with a common gas outlet. Valves are arranged in thesupplies such that when the pressure in the main supply falls to acertain level a valve is actuated to direct gas from that supply notonly to the outlet but also to a pressure actuated warning device, suchas a whistle. When the pressure falls to a lower predetermined level oreven at about the same time with the opening of the first valve, thesupply is switched from the main to the reserve but the warning signalis maintained by gas pressure from the reserve supply and that warningsignal is only stopped when the main supply is restored to a pressureabove the higher of the predetermined levels as by replacing the maincylinder.

From another aspect of the invention there is provided a valvecomprising a main supply inlet, a reserve supply inlet, an outlet and anoutlet adapted to be connected to an audible signal device and a valveelement responsive to main supply pressure and adapted to connect thereserve supply to the signal outlet upon the existence ofa predeterminedlow pressure. Preferably the valve element also connects the reservesupply to the outlet up on the existence of that predetermined lowpressure.

In one embodiment there is provided a valve comprising a main supplyinlet, a reserve supply inlet, an outlet and a supply to an audiblesignal device in which the reserve supply inlet is connected to theoutlet through a first valve element and said main supply is connectedthrough an open passage to the outlet and to said audible signal supplythrough a second valve element, both sad valve elements being adapted tobe operated in response to pressures, said second valve being opened ata higher pressure that said first valve so that when main supplypressure falls to the first predetermined low level the main supply isconnected both to the outlet and to the audible signal supply and uponmain supply pressure reaching the lower of the low levels the reserve isconnected to the outlet and to the audible signal supply.

It is preferred according to this invention to arrange that main supplypressure is exerted on one side of a diaphragm to the other side ofwhich a spring-loaded valve operating ele ment is located so that whenthe pressure on the supply side of the diaphragm falls the valveoperating member is moved to open an appropriate valve.

Conveniently there can be a pressure guage located to indicate outletpressure.

DESCRIPTION OF THE FIGURES OF THE DRAWINGS An embodiment of theinvention is illustrated schematically in the accompanying drawings:

FIG. 1 is a front view of the device of this invention,

FIG. 2 is a side view, partly broken away of the device in Figure 1,

FIG. 3 is a section on the line 3-3 of FIG. 2,

FIG. 4 is a front view ofthe device with parts removed,

FIG. 5 is a section on the line 5-5 of FIG. 4, and

FIG. 6 is a section on the line 6-6 of FIG. 4. DESCRIPTION OF APREFERRED EMBODIMENT The device comprises a front section 10 whichhouses the controls and a rear section in which the valves are locatedand at which the connections of hoses to the cylinders and machines aremade.

The front section of the device comprises a box the front face on whichis an operating knob 31 and a window 32 through which a scale, to bedescribed hereinafter, may be seen.

Within the box there is a gear 33 which is fixed on the shaft 34 of theoperating knob 31. The gear 33 meshes with gear 38 which in turn mesheswith gear 35. Gear 35 has a coaxial pinion 36 which meshes with a gear37 which carries the scale which can be viewed through the window 32.

It will be appreciated that as the operating knob 31 is turned so aregears 33 and 36.

The spindle of the knob extends completely through the housing 10 andinto a tubular section 40. There are two such tubular sections 40 onecontaining the spindle of the operating knob 31 and the other containinga similar spindle which is mounted on the gear 35. Each of the spindlesterminates in a screw threaded section and each of those screw threadedsections carries a threaded abutment piece only one of which can be seenin FIG. 2 and which is numbered 42. The abutment pieces 42 each carry aradial projection 43 which moves in a guide formed in the sidewall ofthe tubular section 40 to preclude rotation of the abutment piece withthe spindle. In this way rotation of the operating knob causes theabutment piece on each of the spindles to move along those spindlestowards or away from the operating knob.

Coaxial with each of the spindles are springs 44 of which one end ofeach is in abutting relationship with the appropriate one of theabutment pieces 42. The other ends of the springs act on valve operatingmembers 45 so that the springs are compressed between the abutmentmembers 42 and the valve operating members 45. The valve operatingmembers are secured to corresponding diaphragms 46 which are trappedbetween the section 20 and the annular flanges 46 of the tubularsections 40. The operating members 45 have annular grooves defined byshoulders 47 and 48 within which the diaphragms and an appropriatestiffening member is located.

Referring now to FIG. 4, 5 and 6 in which the valve section of thedevice is illustrated it will be seen that it comprises a block in whichthere is formed a main inlet passage 50, a reserve inlet passage 51 andan outlet passage 52 with which sections 53 and 54 of inlets and 51respectively communicate. Outlet is indicated on an appropriate pressureguage 55 which is connected to the outlet through a passageway 56. Theinlet 50 has a branch 57 which communicates with an appropriate waringdevice such as for example, a whistle.

Referring now specifically to FIG. 6 there is a cylindrical chamber 60which is divided by a partition 61 into two sections 62 and 63. Thesection 62 is closed by the diaphragm 46 on the operating knob spindleand the section 63 is closed by a threaded closure 64 and an appropriateO"-ring 65. The inner end of the closure 64 is recessed as at 66 toaccommodate a spring 67 which acts between the base of the recess 66 anda valve member 68. The valve member 68 is provided with an annularflange 69 and a locating pin 70 which is coaxial with the spring 67 andserves to properly locate that spring. The valve acts to seal an openingthrough the partition 61 and has an O-ring 72 which cooperates with themarginal edges of defining the opening through the partition. Extendingthrough the opening in the partition is an operating rod 73 whichcooperates with the front face of the operating member 45 so that as thespring 44 urges the operating member 45 towards the valve member, andagainst the action of gas pressure on the diaphragm, the valve is openedand as the operating member is moved in the opposite direction then thevalve is closed.

Referring now to FIG. 5 the structure is basically similar to thatillustrated in FIG. 6 except that the inlet section 51 opens into thesection of the chamber on the valve side of the partition and thesection 54 of the inlet opens into the opposite side of the partition.For the sake of convenience, the similar parts of the valve illustratedin FIG. 5 to those of the valve illustrated in FIG. 6 are allotedsimilar reference numerals and are distinguished by the addition of theletter a.

The operation of the device is as follows. The valves 68 and 68a areadapted to be opened at different pressures, the valve 68 being operatedat a higher pressure than the valve 68a. The springs 44 areprecompressed by rotation of the operating knob to the desired settingwhich will be reflected in the window 32 for example, the valve 68 canbe set to be opened at a pressure of say, 30 pounds whilst the valve 680will automatically be set to open at a pressure of say pounds per squareinch. The higher pressure is the one at which the whistle is connectedand the lower the one at which the reserve supply is opened.

When the device is operating normally with the main supply of gas at ahigh pressure then the flow will be through the inlet 50, 53 to theoutlet 52 with the outlet pressure being indicated on the guage 55. Boththe valves will be closed so that there will be no flow to the whistlenor from a reserve supply to the line 51.

When the pressure in line 50 falls to a preset level then the pressurein chamber 62, which is exerted upon the diaphragm will lessen and thespring 44 associated with that diaphragm will cause it to move and withit the valve operating member 45, to raise the valve 68 from the seatand allow the passage of gas through passage to sound the whistle. Atthe same time the gas will continue to flow through passage 53 of themain inlet to the outlet 52 thence for example, to service outlets.

It is usual for the connection to the main inlet 50 to be made through aT-joint so that there be two cylinders or supplies to the main inlet andas the whistle sounds the anesthetist will open the second main cylinderbut in the event that he is otherwise occupied with more immediatelyurgent tasks and the pressure in the main supply falls below another andrelated low level then the pressure in section 6211 of chamber 61a willcorrespondingly fall until the spring associated with the diaphragm atthat chamber will move forward, and with it will move the valve 68a toallow the reserve supply to flow through passages 51, 54 and through tothe outlet 52. At the same time there will be flow from the reservesupply to passage 53 to maintain the whistle sounding.

The whistle will continue to sound until a full cylinder, or a cylinderabove the first predetermined level of pressure is put onto the mainline.

It is to be appreciated that the device according to this invention issimple and effective and whilst it is not intended to relieve theanesthetist of the principal responsibility for maintaining the supplyit is to a very large extent foolproof.

Further, in many applications the alarm signal and transfer pressurescan be preset so the operating knob and associated gearing can beomitted in those cases.

I claim:

I. A valve comprising a main supply passage, a reserve supply passage,an outlet passage and a supply passage to an audible signal device, saidreserve passage being connected to the outlet passage and to the signalsupply passage through a first valve and said main passage beingconnected through an open passage to the outlet passage and to saidaudible signal supply passage through a second valve element, saidsecond valve element being opened upon the existence of a first lowpressure and said first valve element being opened upon the existence ofa lower pressure than first low pressure.

2. A valve as claimed in claim 1 in which said valve elements are openedby spring loaded valve actuator members, the opening movement of saidactuator members being opposed by main supply line pressure. g

3. A valve as claimed In claim 2 in which the valve actuator members arecarried by diaphragm on one side of which springs act and the othersides of which are exposed to main supply line pressure.

4. A valve as claimed in claim 2 in which the lengths of the springs areadjustable to vary the force exerted upon the actuator members.

5. A valve as claimed in claim 3 in which the lengths of the springs areadjustable to vary the force exerted upon the actuator member.

6. A valve as claimed in claim 2 in which the length of the springs areadjustable to vary that force exerted upon the ac tuator members, andthere is a single control for varying the lengths of both springssimultaneously.

7. A valve as claimed in claim 3 in which the length of the springs areadjustable to vary that force exerted upon the actuator members, andthere is a single control for varying the lengths of both springssimultaneously.

1. A valve comprising a main supply passage, a reserve supply passage,an outlet passage and a supply passage to an audible signal device, saidreserve passage being connected to the outlet passage and to the signalsupply passage through a first valve and said main passage beingconnected through an open passage to the outlet passage and to saidaudible signal supply passage through a second valve element, saidsecond valve element being opened upon the existence of a first lowpressure and said first valve element being opened upon the existence ofa lower pressure than first low pressure.
 2. A valve as claimed in claim1 in which said valve elements are opened by spring loaded valveactuator members, the opening movement of said actuator members beingopposed by main supply line pressure.
 3. A valve as claimed in claim 2in which the valve actuator members are carried by diaphragm on one sideof which springs act and the other sides of which are exposed to mainsupply line pressure.
 4. A valve as claimed in claim 2 in which thelengths of the springs are adjustable to vary the force exerted upon theactuator members.
 5. A valve as claimed in claim 3 in which the lengthsof the springs are adjustable to vary the force exerted upon theactuator member.
 6. A valve as claimed in claim 2 in which the length ofthe springs are adjustable to vary that force exerted upon the actuatormembers, and there is a single control for varying the lengths of bothsprings simultaneously.
 7. A valve as claimed in claim 3 in which thelength of the springs are adjustable to vary that force exerted upon theactuator members, and there is a single control for varying the lengthsof both springs simultaneously.